How can I check my csv file has uploaded correctly?

When you upload a csv file in the admin panel it will state the number of rows updated. If you have multiple countries/states on 1 line then the number of rows will be higher than the actual number of rows in the csv file.

To see the actual data you can look in the database, where it will show you how the data is stored internally. Therefore if you have concerns about the rates not showing correctly you can check the database first if you are not 100% on the format of the csv file.